Blue Circle around eyeball

My father has a blueish/purpleish circle around his eyeball.  He also has other medical conditions.  What could cause this????

[Sandy Feldman, MD, MS]

The sclera of the eye is normally white while the choroid has pigment cells in it and is dark blue in color.  As we age, the sclera thins and we can see a bluish color.  This may appear as a plaque near the nose on the white part of the eye.  Other causes of thinning of the sclera and blue appearance include Ehler's Danlos syndrome, pseudoxanthoma elasticum, Marfan's syndrome which are systemic diseases of the elastic tissue of the body.  Blue sclera can also be associated with long term use of medications such as corticosteroids.  I would recommend that you father see an eyeMD to have his eye checked.